RS6000_MCOUNT and -fpic

[gp@qnx.com]

Hey, all.
 
Not sure of this 'fix', so I want to run it by you.  Basically, with gcc-
3.3.1 and binutils 2.12.1, the rs6000 output_function_profiler() in rs6000.c 
always emits "bl RS6000_MCOUNT" for profiling, which turns out to be "bl 
_mcount".  

In pic code (like a shared object), when I compile it with "-p", the "bl 
_mcount" gets turned into "bl <address of this bl instruction>", so I loop 
infinitely on a self-referencing branch and link.  If I change that to a "bl 
_mcount@plt" then all is good.

What I did was change the following line from output_function_profiler() in 
rs6000.c:

  fprintf("\tbl %s",RS6000_MCOUNT);

to:

  if (flag_pic && DEFAULT_ABI == ABI_V4)
    fprintf("\tbl %s@plt",RS6000_MCOUNT);
  else
    fprintf("\tbl %s",RS6000_MCOUNT);


- Does that look reasonable?  In my case, the _mcount symbol is being pulled 
in from our pic libcS.a.  
- Why would I end up with a self-referencing "bl" instruction without the
"@plt"?  Any idea?  I think I've seen it before, so even though it looks 
like a bug, it might be a feature (I guess...)  :-)

Thanks.
GP